Automated highway systems utilize sensing and computing equipment to assist operators of motor vehicles in safely and comfortably travelling along a suitably equipped highway. A future automated highway system minimally provides supplemental information to the operator and optimally permits entirely autonomous machine control of each individual truck or automobile without requiring substantial operator intervention. Such an automated system must be capable of detecting roadway obstructions and other traffic, steering the vehicle and controlling its speed, maintaining a safe spacing between vehicles and detecting information such as roadway weather conditions, location for navigational purposes and upcoming highway structures, such as exits.
An extensive variety of automated highway system architectures have been proposed. Several use radar systems which sense obstructions in the forward or side directions, such as other vehicles and guide rails. Radar has the advantage that it is an active system giving all-weather and day or night performance, and has the inherent capability of sensing distance and direction to reflective targets. Radar has also been used for the guidance of airborne ordnance delivery vehicles, such as guided missiles and airplanes. Modern radar scattering technology also allows echo signatures from objects to be interpreted and used for providing additional information. However, within the knowledge of the inventors, a forward-looking radar system has not been developed for highway motor vehicle guidance, i.e. steering.
It is an object and feature of the present invention to provide a highway vehicle guidance system utilizing radar which looks backwards or looks both backwards and ahead of the vehicle to detect information both for guiding the vehicle along the highway and for detecting prerecorded information about upcoming highway structures and conditions.